Summary

The investigators goal is to optimise physical activity interventions to help previously
inactive women improve their body shape and composition. Many people seeking to lose weight
or improve body composition initiate an exercise programme. The most common recommendation
of an exercise intervention for someone attempting to manage their weight, has been to
'prescribe' the recommended 150 minutes of exercise per week (World Health Organisation),
often using one mode of exercise. An alternative approach might be to offer a portfolio of
activities, from which the exerciser can pick and choose, to facilitate greater amounts of
physical activity. The problem with this is how do you account for the different intensities
of walking, washing the car, playing badminton, cycling, jogging, etc? In this study, the
investigators will try to overcome this barrier by allocating a number of "physical activity
points" to each activity. Using this physical activity points system, participants will be
provided with a points target that they can meet using any combination of activities.

The investigators research aim is therefore to compare this points-based system against the
traditional 5x30minute prescription (and sedentary control) for their ability to help
previously inactive women to drop a dress size, increase fat burning, positively change
their body composition and tone their tummy.

Study Design

Participants will be asked to choose one activity and stick to it for the duration of the intervention. Participants will be able to choose between brisk walking/slow jogging or cycling. The intervention will require the completion of 30 minutes of chosen activity on 5 days of the week, which will be recorded in a physical activity diary.

Participants will be asked to achieve a pre-set, individualised points target for physical activity each week. Points are acquired through the completion of a minimum 10 minutes of activity, choosing from the extensive list of activities provided; for example, 10 minutes of jogging achieves 4.5 points, whereas 10 minutes of washing a car achieves 1.5 points. The target will be 35-40 points per week, which equates to approximately 6 points per day. Any combination of activity, duration and frequency can be selected.

Participants will be asked to maintain their normal activities and diet. They will be added to a waiting list to receive either exercise intervention after completing the 24-week trial period, so that they do not miss out on the opportunity to receive the exercise intervention.

Primary Outcomes

Measure

Change in body composition (fat and fat-free mass in kg)

time frame:
4 weeks, 12 weeks and 24 weeks

Secondary Outcomes

Measure

Perceived body shape

time frame:
4 weeks, 12 weeks and 24 weeks

Maximal aerobic capacity

time frame:
4 weeks, 12 weeks, 24 weeks

Fat oxidation rates

time frame:
4 weeks, 12 weeks and 24 weeks

Body tone

time frame:
4 weeks, 12 weeks, 24 weeks

Eligibility Criteria

Female participants from 25 years up to 50 years old.

Inclusion Criteria:
- Female
- Aged 25-50 years old
- Inactive (less than 150 minutes of moderate-intensity aerobic physical activity per
week)
- BMI 25-35 kg/m2
- Good general health, as assessed by the School of Sport, Exercise and Rehabilitation
Sciences' General Health Questionnaire
- Willing to strictly comply with all study procedures and restrictions
- Willing to participate, as demonstrated by voluntary written informed consent
Exclusion Criteria:
- Positive result from the urine sample pregnancy test
- Currently breast feeding
- Currently participating in another clinical trial deemed to potentially interfere
with this study
- Current or recent (within the last 30 days) smoker
- Currently taking prescription or non-prescription medication that may interfere with
metabolism (including beta-blockers, insulin, bronchodilators, anti-inflammatory
agents, thyroxine and medication/supplements that in the opinion of the investigators
may affect metabolism).

Additional Information

Official title

The Effect of Physical Activity Intervention Flexibility on the Time Course of Changes in Body Composition and Metabolism

Trial information was received from ClinicalTrials.gov and was last updated in October 2016.

Information provided to ClinicalTrials.gov by University of Birmingham.